Windmill



Dec. 27, 19270 1,654,165

D. E. FELT WINDMILL Filed June 18, 1924 4 Sheets-Sheet l /6 PM 19 2a fizz/1E rZT7i-- D. E. FELT WINDMILL 4 Sheets-$heet 2 Filed June 18, 1924 Dec. 27, 1927.

D. E. FELT WINDMILL Filed June 18, 1924 Sheets-Sheet s Dec; 27, 1927. 1,654,165

D. E. FELT W INDMILL Filed June 18, 19.24 4 Sheets-Sheei 4 Patented Dec. 27, 1927.

UNITED STATES 1,654,165 PATENT OFFICE.

none E. ram, OF CHICAGO, ILLINOIS.

WINDMILL.

Application" filed June 18,

frame, or tower, preferably of triangular form, within which one or more paddle wheels are mounted for rotation under the influence of the wind, and the invention re sides 'nin'iarily in the means by which the paddles of said wheel, or wheels, are mounted and controlled, though certain features of novelty are also present in other parts of the construction and plan of operation.

A. very valuable feature of the invention is in the hinging of the paddles at their outer edge, which obtains certain marked advalr s in operation whichwill presently ape pi ,r. With the paddles so mounted, they are subject to effective wind pressure throughout the 'reater part of their rotation around theaxrs of the wheel and they feather much, more satisfactorily than if they were hinged at their inner edge, or me dially. ii ging the paddles in this manner also iitontributes materially to the functioning of the speed governing device to be later described and to starting the mill up after it has-been thrown out of operation. This hinging of the paddles at their cages also eliminates the presenceof a projecting blade surface on the opposite sides of the pivotal point. In other words, there is no short tail surface projecting from the opposite side of the pivotal point of the blade.

An important object of the invention is to provide such a device that will utilize greater volume of wind passing therethrough than has been possible heretofore. This is accomplished by arranging and constructing vanes or paddles so that they will be controlled by centrifugal force and so that they will have the eliect of a turbine throughout the major part of a revolution. further object of the invention is the pr sion of a wind engine which may be thrown out of the wind to a large extent when not in operation, thus overcoming the princi al objection heretofore attributed to vertical axis mills, namelythat they run continuousiy whet-her or not their service is needed and, therefore, soonwear out. The

1924. Serial no. 720,748.

mechanism employed for this purpose per mits the stopping of the null in convenient manner, provision. being made forbcausing' the paddles, or vanes, of the rotatable wheel to assume a position which not only stops the rotation of said wheel, but also relieves the wheel and tower from excessive Wind pressure, thus rendering it possible to use a light frame structure which will offeriminimunrobstruction to the free passage of the wind to and from the vanes of the Wheel.

a 'l. he invention also contemplates the provision of means for governing the speed of the mill so that it will not race in a high winda feature of veryv great importance,

since all mills of this general type, of which 1 amaware, have been subject to this difficulty of racing, particulariy in generating electricity.

It also an object of the invention to provide a construction which utilizes, inmost practical manner, the advantages of the ver tical axis type of windmill, among which the following may be mentioned: By using a vertical shatt, the great loss of power attendant upon the use of miter gears to transmit power from I the wheel down to the ground, may be avoided without placing the generator at the top of the tower-the only means heretofore attempted by manufacturers, so far as I am aware, for avoiding this drlhculty. The vertical axis construction also makes it possible to employ awheel of small diameter and long axis in order to attain relatively high speeds, which are desir able in generating electricity and also in pumping where the elevation is slight and a screw or helicoidalitube is used forraising the water, it being, of course, possible to use a larger diameter when a slow speed is desirable. Another advantage is that such a mill will operate regardless of the direc' tion in which the wind blows, being always orientated and thus avoiding the use of a fan and other complicated mechanism for rotating the mill to present the proper face to the wind. 7

Another object of my invention resides in the arrangement whereby a plurality of mill units may be verticallysuperimposed so as to be clutchable to the given vertical power shaft, whereby these units may be independently clutched'or connected to this shaft. Numaious other objects and advantages of the invention will be apparent as it is better understood from the following dewhich is very objectionable,

scription, which, taken in connection with the accompanying drawings, discloses a preferred embodiment thereof.

Referring to the drawings,

Figure 1 is a side elevation partially broken away, of awindmill apparatus in which my invention is embodied, one of the units thereof being shown out of action and the others set to operate;

Fig. 2 is a plan view of one of the paddle Wheels, being taken transversely through the frame substantialy upon the section line 22 of Fig. 1 and showing the arrangement of the parts when the wheel is not operats;

Fig. 3 is a similar view taken substantially upon the line 3 3 of Fig. l and showing the arrangement of the parts when the wheel is operating;

Fig. 4- is an enlarged sectional view, taken substantially upon the line l-Lt in Fig. 3;

Fig. 5 is a. transverse sectional view talien substantially upon the line in l and showing the throw-out and clutca operating lever;

Fig. 6 is an enlarged sectional view when substantially on the line 66 of Fig. 5; and

Fig. 7 is a detail sectional view, taken substant-ia-lly upon the vertical line 7-'T of Fig. 6.

The tower in the present instance, of triangular form and comprises angular up rights 11, connected by horizontal. bars 12 which are turned down at their ends indicated at 13, and secured to said uprights by means of bolts 14. The mill preferably consists of a plurality of separate units ranged upon a sectional vertical shaft 15, which is journaled in bearings 16 and 1."? at the top and bottom of the structure and in triangular reinforcing plates 18 disposed between the different units of the mill and secured at their corners to the bars 12 (see Fig. 5). r

The different units consist primarily of wheels formed by upper and lower members 19 and 21, which are secured at their center to a section of the shaft 15 and have hinged thereto near their periphery the vanes or paddles 22 which operate in the wind and produce rotation of the wheel. These members are shown on the drawings solid disks, though it is contemplated that spoked or open wheels might be used quite as advantageously if desired. Said paddles 22 are pivoted upon shafts 23 extending through and secured to the upper and lower members 19 and 21. t will be noted, from an inspection of Fig. 3 that in the construction here illustrated, the paddles or vanes operate almost wholly within the periphery of the members 19 and 21 and that the pivot point is, therefore at the outer edge there of. Said paddles are preferably formed of sheet metal and are curved, as indicated in neaaaee Figs. 2 and 3, the edges thereof being hem: around the shafts 23 and back upon the body as indicated at Referring now to Figs. 2 and 3, the relatire positions of the vanes when the wheel is out of the wind and when it is operating may be observed. Assuming that the wind is blowing in the direction indicated by the arrows in liig. 3, the paddles 22 (except those returning against the wind) will be disposed with their inner ends in contactwith lined stops or the ends of levers 26 which may be of any suitable shape and are preferably of bell-crank shape as shown are pivoted at 27 on the upper surface of the member 21 and correspond in number to the number of said paddles 22. The are described by the inner edges of the paddles as they feather when returning against the wind indicated by dotted lines in Fig. and it will be seen that this arrangen'ient causes said paddles to be subjected to ellectire wind pressure throughout the major portion of their travel about the axis of the wheel. \Vith the wind blowing as indicated, the vanes or paddles on the windward side are against the levers 2S and form battles, the angle of which gradually increases as they travel about the center of the mill uir til they present a full. face to the wind, and then gradually decreases until they are substantially in line with the wind. After passing the point at which the pzuldles are in line with the wind, the wind engaging behind the paddle which is free to turn about its pivot swngs the paddle ouivmrdly and against the .l red stop The motion of the paddle between the stop 26 and the fixed stop 25 is controlled. by the centrifugal action of the weight 4.9 which is of suflicient weight to slow down this action so that the motion of the paddle will be gradual the paddle comingin contact with the tired stop sub; antially at the position shown in Fig. or later. This operation accomplishes a reversal of the paddle so that it forms a baflle to the wind on the return side of the wheel :nd as sts in turning the mill until after the position shown at the upper right hand side of Fig. 8. From the posit on just mentioned around to the windward side. the vane merely feathers in the wind and "'aclually returns to the position against the stop 26 at the windward side of the mill. From the above description will be noted that throughout the first degrees of re\'olution a turbine effect is obtained, which gradually develops into direct pressure and that th ougheut tie next 90 degrees the directpress re gradually develops into a turbine, and at approxiu'iately 180 degrees the blade reverses and a turbine eti ct is obtained throughout approximately (30 dcgrees more of revolution, and since the shifting of the blade on the side of the mill, op

ferred through. the shaft 23 to the milland. force is exerted in the directronof rotation;

thereof. By this arrangement approximately 250 degrees of revolution ofeach' blade is effective and a greater power may be obtained from a given volume of wind with a small un-it. i

hen it is desired to stop; the mill, the levers 26 are moved from the position shown in Fig. 3 to that shownin Fig. 2, which permits all the paddles, except those on the lee side of the wheel, to feather at the same time, thus offering slight obstruction to the wind and relieving the wheel fromeifective pressure. The strain on the tower isalso: greatly reduced. The are described by the inner ends of the paddles when thus permitted to feather is indicated by dotted lines in Fig. 2, the limits of this are being thestops 25 at one end and stops 25 (the purpose of which will presently appear) at the other end, It will be obvious that, regardless of the way in which the Wind blows, said paddies may feather in the manner and with the results just indicated. This is a very important advantage, since it permits oifthe use of a lighterframe and avoids danger of the structure being torn to pieces in a gale.

The manner in which the levers 26 are controlled to stop the mill and to throw the paddles out of the windwill now be described, reierence being had particularly to Figs. 3, i and 6. Said levers 26 have inner extensions 28 disposed above apertures 29 in the-member 21 (seeFig), the endsof said extensions being disposed beneath straps 31 having their ends turned'down and secured to said member 21, as indicated at 32. Said extensions 28 normally are held against the sidewalls of said straps by means of springs 35 secured at one end to said extensions and at the opposite end to studs 36 up This disposes standing from the disk 21. the levers 26 in the path of the paddles 22* and provides for theoperation of the latter in the manner previously described. hen it is desired to throw the paddles out ofthe wind, said levers are acted upon by means-of inclined lingers 37, extending through the apertures 29 and secured to the upper sur-- face of a vertically movable disk 38. Said disk is slidably mounted upon the shaft 15 above a supporting disk 89 and said disks are adapted to be lifted together by meansoi throw-out and clutch operating lever ll pivoted at 42 to a depending ear 43 on the plate 18 (see Fig. 6-) and having a biijurcated, upwardly turned inner end portion 2L4 extendingthrough slots 45 in said plate 1 8 and adapted to contact witlrtheunder surface of said disk 39 (see Fig; 7). The outer end of said lever 411's normally held in. raised-positionby nieansof a springi le secured thereto at one end and secured atits opposite end to 1.1001147 provided upon one of the uprights 11. A wire, or cord 48 is secured tothe outer end ofeachlever 41 and. carries atits lower end. an. apertured strip l8 'adaptedto ho'olrover aprojection.

50 provided near-the baseot one of the uprightsll to hold thelerer down against the'. tension oi the spring ld VVlieir said lever: is drawn downwardly, hediskl 38 and. fin; gers: 37 are raised,.,sa;id iin:gers,f in. rising? through the apeit res 29, havinga cam ac 'tion upon the lever extensions 28,. forcing them against the tension of; the springsto the position shown in Fig. 2. .This promptly brings the-wheel to substantial rest, in which condition it remains until: the lever 41 is again. raised.

Whenit is desired: to again start operation of the wheel, the appropriate'wire L8 may be released, allowing the lever n to assume the normal raised positionwhlch Withdraws the lingers 37 from engagementwith the le-- ver extensions 28 and permits the spr1ngs35 to restore the levers 26 to the operative position of Fig. Suchof the paddles as are at tlllS- time swung around beyond the ends of said levers 26 must obviously be-a'noved baclrjto the position of F ig. 3, and this is accoi-nplished in a short time by the Wind has and forcin itself acting upon the PM l the levers 26- inwardly against the tensioi'i or the springs 35 to provide clearance. The levers 26 are curved inwardly at and are formed with notehesbtl, which serve to re tain the paddles 22 incontact with said levers in the event that said paddles strike against the levers but do not move them suiiiciently to produce the necessary clearance. lVith the paddles held insaid notches, the wind blowing therea-gainst will help to rotate the Wheel, From this position, the

paddles, when suitably presented to the wind, may readily be moved past the endsol' the levers and into the position o'tFig';

3. Furthermore, the stops 25 are provided to'h'old said "paddles within the circumfe-r ence of the wheel, in order that they may.

be readilyrestored to this position.

In order to control the speed and power oi themill and prevent racing in a high wind, I provide governing means, COIH'PIIS- ing' weights 49 carried upon supporting rods 51 projecting from the outer edgeoI" the paddles. Said weights may be positioned at desired distance {from the paddlesand when the wheel attains a predetermined rate of peripheral speed, the weights by: centrifugal action se'rveto regulate the action of the paddles and to increase the range of action thereof. ."Vith this simple form of governing mechanism, a degree of uniformity of speed, which is highly desirable ingeneratrng electricity, 1S obtalned ZXDCliJll'Q; apparatus is protected from the results of excessive speed.

The machine as shown in the drawings is, for certain uses, preferably constructed of a plurality of units, each involving independent paddle wheels and controlling mechanism. In order that the different units may be used separately or in unison, I employ clutch mechanism associated with each throw-out lever 11, and perhaps best illustrated in Figs. 1, 6 and 7 The shaft 15 is formed in sections and clutch members 52 and 53 are secured to the adjacent portions of said sections between the different units of the mill. The lower end of each shaft section is journaled in suitable bearings 55 provided in bearing plat-es 56 secured to the under side and extending downwardly from the plates 18. Said bearing plates are supported from the uprights by means of twisted bars 57, bolted at their outer ends to the uprights 11 and secured at their in ner ends to the under surface of said plates 56. Referring now particularly to Fig. 7, it will be noted that the inner bifurcated end of the lever 11 is provided with inwardly extending pins 58, engaging in a groove 59 in the clutch member 58. Depression of the outer end of said lever ll, therefore, results in lifting said clutch member 53, which is splined on its shaft section, out of engagement with the member 52, disconnecting the wheel next above from the next lower section of the power shaft. This movement of the lever 41, as has been heretofore stated, also stops the wheel, permitting the vanes 22 to feather and thereby relieving the wheel and tower from excessive wind pressure.

The shaft 15, at its lower end, carries a pulley 61, over which takes a belt 62 driving a smaller pulley 68 mounted on an armature shaft 6 1 of a generator 65, which is positioned in a frame 66 on the ground. The armature 67 of said generator has been diagrammatically shown -in Fig. 1 and it is contemplated by the present invention that this armature may be of relatively large diameter so that the peripheral speed thereof may be definitely related to the peripheral speed of the wheels formed by the disks 19 and 21. The ratio may be obtained by appropriate relative sizes of the pulleys 61 and 63 and by the diameter of the armature, the approximate relation, in the present instance, being on the basis of three revolutions of the armature 67 to one of the wheel.

It should be noted that a further distinct advantage occurs from the hinging of the vanes 22 at their outer edge, since this evercomes the difliculty heretofore experienced of having the vanes returned on one side of the mill against the wind, with consequent great loss of power.

The frame, or tower is constructed in such manner as to offer slight interference with the wind approaching the wheel, thus making it possible to use relatively light construction materials and also avoiding the danger of being blown to pieces in a gale. In the construction here shown, the frame is of triangular form and the uprights 11 extend radially with respect to the wheel so that the wind will either pass between said uprights, or, if itstrikes directly thereagainst from one of the angles of the triangle, the surface encountered will be small and will offer slight obstruction to the free passage of the wind to and from the wheel.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description, and it will be apparent that various changes may be made in the form, construction and arrangement of the parts without departing from the spirit and scope of the invention, or sacrificing all of its material advantages, the form hereinbefore described being merely a preferred embodiment thereof.

I claim:

1. A windmill, comprising, a support, a rotatable member having a vertical axis in said support, a plurality of curved vanes pivoted at their outer edges to said member and disposed about the circumference of said member so as to be accessible to the wind from all points about such circumference and devices constructed and arranged to be operatively associated with said vanes, whereby said vanes are adapted to receive power from wind passing through the mill throughout a major portion of a revolution of said rotatable member.

2. A windmill, comprising, a frame, a rotatable member having a vertical axis in said frame, a plurality of vanes hinged at their edges to said rotatable member, and devices rigidly attached to the vanes opposite their hinges and adapted to control the vanes by centrifugal action to receive power from wind passing through the windn'iill throughout the major portion of a revolution of said rotatable member.

3. A windmill, comprising, a support, a rotatable member having a vertical. axis in said support and open to the wind at all points, a plurality of curved vanes hinged at their peripheries to said member and means for controlling said vanes, whereby the wind pressure acts on said vanes with both direct and turbine effect during the travel of said vanes around the axis of said member.

4. A windmill, comprising, a. rotatable member, having a vertical axis, a plurality of vanes pivoted to said rotatable member and adapted to rotate said member in the wind, and means for governing the speed of rotation of said member, said means comprising devices rigidly attached to said vanes and arrangedito-resist movement'ofthe vanes,

with: respect: to said rotatable member by centrifugal action.

5'. A windmill, comprising, a rotatable member having a vertical axis, a plurality of vanes pivotedat their edges in said ivheel forthe OPQIfltlOIltllOI'GOf andhavmg a pluralityof operating positions, fixed andmov vanes-to permit said vanes t'o feather inklhe wind: and offer substantially equal and relativelyslight obstruction thereto; Y

6: A windmill;- comprising a rotatable memberhaving a verticalaxis, a plurality of'vaneshinged to'saidmember and operableinttheWind to rotateitlie latter, means for limiting the movement of said-vanes to cause them? to remain in the Wind, and means for shifting said last-mentioned means to permit substantially all the vanes to feather whenroperation of'the mill is not desired.

A windmill, comprising a: rotatable member having avertical axis, a plurality of vanes pivot'ally; secured" to said member and? operable inzthewind to rotate the latter, fixed outer stops for said vanes, pivoted levers disposed inwardly" from said stops a-nd adapted to limit the. inward movement of the vanes, and means for turning said levers upon their pivots to move them: to non-obstructing positionpermitting substantially all thevanes to featherin the Wind when it is desired to stop the operation of themill. i

8L windmill, comprising. a rotatable memberhaving' a vertical axis, a plurality of vanes pivotally secured to' said member and operable in. the Wind to rotate the'latter, fixed outer stops'forsaid vanes, pivoted levers disposedinwardlyfromsaid stops and adapted to limit the inward movement of the vanes-, spring means" for holding said leversnorma'lly'in obstructing position, and

vertically movable controlling device for shifting said levers" to non-obstructing position permitting substantially all the vanesto feather in the Wind Whenit is desired to stop" the operation of the mill.

'92 A windmill, comprising a rotatable member'having a vertical axis, a plurality of vanes pivotally secured to said member and operablein the wind to rotate the'latter; fixed outer stops for saidvanes, pivoted levers disposed inwardly from said'stops and adaptedto limit the inward movement of the vanes, spring means for holding said levers normally in obstructing position, and a'manually operable device-for shifting saidlevers to non obst'ructing position permitting substantially all the vanes to feather in the wind. when it is desired to-stop the opera tionof the mill.

10.1A windmill, comprising a rotatable, member having a vertical axis-,a plurality of vanes pivotally secured to said member and operable in the wind to rotate the latter, fixed outer stops for said vanes, bell.- crank levers disposed inwardly from said, stops and adapted toxhave one arm thereofi normally positioned in the path of movementof said vanes to maintain thelatter in the Wind, and manually operable means adapted to act upon the other arms of said levers-to move the latter to non-obstructing position permitting substantially all the vanesto feather in the Wind When it is desired: to stop the operation ofthe mills 11. A windmill, comprising a verticalshaft, a rotatable member mounted onsaid shaft, a plurality of vanes pivotally secured? to said member and operable in the wind to rotate the latter, fixed outer stops for said vanes, movable inner stops adaptedv'to normally confine said vanes within a limited path of movement, means for moving said inner stops to non-obstructing position permitting substantially all the vanes to feather in the WlIl'Cl, and a clutch device associated With said last-mentioned means for discons necting said rotatable member from said shaft. y

12: A Windmill, comprising a vertical shaft, a plurality of rotatable Wheels mounted on'said shaft, \vind vancs hinged to said Wheels near the periphery vthereof, means for confining saidvaneswithin a limited path of movement to maintain them in the Wind, means associated with. each of said Wheels for releasing said van-es to permit them to feather inthe Wind, and a clutch device associated with each of said lastrmentionedmeans for disconnecting the associated Wheel from said shaft.

13. A Windmill, comprising a rotatable member having a vertical axis, a plurality of vanes pivotally secured to said member and operable in the Wind to rotate the latter, fixed stops on said; member at the opposite sides of the pivot points of the vanes, and means arrangeable in the path of movement of said vanes as they would normally feather between said stops for holding the vanes in the Wind, one of said stops coo )erating;with said last-mentioned means for holding the vanes inthe wind and the other assisting in restoring the vanes to operative position when the mill is started up-afterbeing out of operation. r

14:; A Windmill, comprising a rotatable member having a vertical axis, a plurality of vanes pivotallysecured'to said member and operable in the Wind to rotate the latter, fixed outer stops for said vanes, pivoted levers disposed inwardly from said stops and adapted to be moved to and. from position obstructing the movement of the vanes whereby to maintain said vanes in the wind or to permit the vanes to feather when operation of the mill is not desired, said levers being notched at. their outer ends and. being yieldable under pressure of the vanes to permit the latter to be restored to operative position after said levers have been set to cause the mill to operate.

15. A windmill, comprising, a frame, a rotatable member having a vertical ax in said frame, a plurality of vanes hinged to said member adjacent the periphery thereof, spaced means for controlling said vanes to produce effective pressure in at least two positions, and means for governing the movement of the vanes between said spaced means to control the speed of rotation of said member.

16. A windmill, comprising, a frame, a rotatable member having a vertical axis in said frame, a plurality of vanes pivoted to said member near to the periphery thereof, spaced means for controlling said vanes to produce effective pressure in at least two pivotal positions, and means for governing the movement of the vanes between said spaced means to control the speed of rotation of said member, said means comprising devices adapted to control the movement of said vanes between the spaced means by centrifugal action.

17. A windmill comprising a frame, a rotatable member having a vertical axis in said frame, a plurality of vanes hinged at their edges to said rotatable member, and means rigidly attached to the vanes opposite their hinges and arranged to have relatively slight wind resistance and relatively great centrifugal action, and to control the speed of rotation of said rotatable member.

18. A windmill, comprising a frame, a. rotatable member having a vertical axis in said frame, a plurality of vanes hinged at their edges to said rotatable member, and means rigidly secured to the vanes and extending opposite the hinges thereof adapted to control the speed of said rotatable member by controlling theoperating movement of the hinged vanes.

19. A windmill,comprising, a frame, a retatable member having a vertical axis in said frame and a plurality of vanes hinged at their edges to said rotatable member, and means for controlling and regulatingthe speed of said rotatable member, said means, comprising, adjustable balancing weights rigidly attached to the vanes and positioned opposite the pivots thereof.

20. A. windmill, comprising, a frame, a rotatable member having a vertical axis in said frame and a plurality of vanes hinged at their edges to said rotatable member, and means for adjusting the speed of said rotatable member, said means, comprisin an arm secured to the vanes and extending across the pivot thereof and a balancing weight attachable to said arm at varying distances from said pivot.

21. A windmill, comprising. a frame, a rotatable member having a vertical axis in said frame, a plurality of vanes hingeiil at their edges to said rotatable member, and means for regulating the speed of said ro tatable member, said means comprising balancing weights rigidly secured to the vanes and extending opposite the pivots thereof.

22. A windmill, comprising, a frame. a rotatable member having a vertical axis in said frame, a plurality of vaneshinged at their edges to said rotatable member, and means for regulating and assisting in the rotation thereof, said means comprising devices rigidly attached to the vanes and adapted to control. the movement thereof about their hinges by centrifugal action.

23. A windmill, comprising a rotatable member having a vertical axis, a plurality of vanes pivotally secured to said member and operable in the wind to rotate the latter, fixed stops on said member at the opposite sides of the pivot points of the vanes and in the path of movement thereof, and means arrangeable in the path of movement of said vanes as they would normally feather between said stops for holding the vanes in the wind. 7

24. A windmill, comprising, a frame and rotatable member having a vertical axis in said frame, a plurality of vanes hinged at their edges to said rotatable member and a weight attached to each vane, said weight being constructed and arranged to shift in a horizontal plane when acted upon by said centrifugal force, whereby to automatically cause a pivotal movement of said vane.

25. A windmill, comprising, a frame and rotatable member having a vertical axis in said frame, a plurality of vanes hinged at their edges to said rotatable member, a weight for each vane, fixed and shiftable stops for each vane, said shitl'table stops being capable of movement so as to be out of contact with said vanes in one position and to be movable into contact with said vanes to form rigid abutments, whereby to cause the wind acting on said vanes to rotate said member at. a substantially uniform speed.

26. A windmill, comprising. a rotatable member having a vertical shaft. a plurality of vanes pivotally secured to said member and operable in the wind to rotate the latter, fixed and movable stops on said member, a clutch for com'iecting said rotatable member to said vertical axis and means for shifting said clutch and said movable stops.

27. A windmill. comprising, a support. a rotatable cage having a vertical axis on said support, said cage being open to the wind from all sides and a plurality of vanes havpivotally mounted at their edges to said cage, ing one edge of each vane pivotally mounted said vanes being curved and devices conon said cage, said vanes bein relatively thin structed and arranged to cooperate with said and being curved so as to e substantially vanes, whereby to produce effective wind 5 cradle shape in cross-section and a plurality pressure of alternately direct and turbine of stops on said cage for determining cereffect upon said vanes throughout the major tain positions of saidvanes. portion of their travel around the axis of 28. A Windmill, comprising, a rotatable said cage. cage open to the wind from all sides and 1. having a vertical axis, a plurality of vanes DORE E. FELT. 

